Re: [Discuss-gnuradio] Problem using the dbs card

When I first got my DBS_RX card, I plugged it into a low-noise
amplifier, and tuned it to the
GPS L1 frequency, with a circular waveguide feedhorn on the front of
the LNA. As expected
the GPS L1 carrier appeared in the fft display. Placing a sheet of
metal in front of the feedhorn
caused the L1 blip to go away.

Around this time (I got an early DBS_RX card), there was some concern
about some resistor values in
the amplifiers used between the MAX2118 and the A/D. Some values
caused "deafness". Matt had
published instructions on how to fix the problem yourself--assuming a
steady hand, and excellent
eyesight. I think I've seen rotoviruses that were larger than some
of the components on modern
hardware :-) :-)

But I never saw the "deafness" problem, so I never bothered to
implement the "fix".

EVENNOU Frederic RD-TECH-GRE wrote:

Problem using the dbs card

Hi everybody,

I started using the
gnuradio platform some few weeks ago, and I've been trying to use the
dbs_rx card. I made some few tests to practice myself on the way to use
this card, but unfortunately I didn't have any successful result.

I've been using a
python program named dbs_fft.py to have a look at the spectrum in a
range of frequencies that I specify. I made some few tests by emitting
a sine wave at 1GHz (and then around this frequency), but I've never
been able to get it with the dbs card, whereas I can see it very
clearly on a spectrum analyzer (level == address@hidden). At emission, and
reception, I have some antennas working in that band and antennas are
separated by 50cm. On my display screen I just receive some noise so I
must receive some samples from the dbs_rx card.

I made the same test
at lower frequencies and using the TVRx card to receive the signal, and
it works pretty well.Did someone have the same
problem with this card, and is there anything special that can be done
to check if my dbs_rx card works properly ?